Dying or diseased Privet Hedge

Nothing to lose by cutting hard back then mgkelly. Definitely worked for me.
If no new growth shows by mid September or so you can think of replacing your hedge.

I think Sheal’s suggestion of griselinia is a good one....I have a hedge of it here and it is robust and attractive.

 

It does seem your hedge is beyond retrieving now MG but it may be worth cutting it back and seeing if it re-shoots.

If you decide to dig it out the soil will need some work before replanting there.